Description
The
BENTLY 3500/92 is a high-performance Keyphasor and Speed Monitor module designed as part of the BENTLY 3500 Machinery Protection System. Engineered for critical rotating machinery applications, the
3500/92 provides precise measurement of shaft speed, direction, and keyphasor signals, enabling accurate monitoring of machine dynamics and facilitating predictive maintenance.
As a core component of the 3500 series, the BENTLY 3500/92 ensures reliable detection of rotational speed variations, gear mesh issues, and timing events, which are essential for maintaining the efficiency and safety of turbines, compressors, and generators. Its robust design and advanced signal processing capabilities make it a trusted choice for industries where machinery downtime must be minimized.
Parameter |
Details |
Model |
3500/92 |
Brand |
BENTLY |
Type |
Keyphasor and Speed Monitor Module |
Input Voltage |
18–30 VDC (nominal 24 VDC) |
Frequency Range |
0.1 Hz to 10 kHz (speed: 0.1 RPM to 1,000,000 RPM) |
Signal Inputs |
Two channels for proximity probes or tachometer signals |
Output Signals |
Analog (4–20 mA, 0–10 VDC) and digital (TTL/CMOS) |
Resolution |
0.1 RPM (dependent on input signal quality) |
Compatibility |
BENTLY 3500 Machinery Protection System |
Temperature Range |
-40°C to +85°C (-40°F to +185°F) |
Mounting |
Rack-mounted within 3500 Chassis |
Certifications |
CE, CSA, ATEX (for hazardous environments) |

BENTLY 3500/92
The BENTLY 3500/92 stands out for its dual-channel configuration, allowing simultaneous monitoring of primary and redundant signals to enhance system reliability. It offers advanced diagnostic capabilities, including signal validity checks and fault detection, which reduce the risk of false alarms and ensure data integrity.
One of its key features is the ability to support multiple probe types, including inductive proximity probes and optical tachometers, providing flexibility for diverse machinery setups. The module also incorporates high-speed signal processing to capture transient events, such as start-up and shutdown sequences, with exceptional accuracy. Its rugged construction and wide temperature range make it suitable for harsh industrial environments, from offshore platforms to high-temperature power plants.
The BENTLY 3500/92 is widely used in industries such as power generation, oil and gas, and manufacturing to monitor the rotational speed and keyphasor timing of critical machinery. It is essential for applications requiring precise synchronization, such as steam turbines, gas engines, and gearboxes.
Case Study: A combined-cycle power plant in Saudi Arabia deployed the 3500/92 to monitor the speed of its gas turbine during load changes. The module’s real-time speed feedback allowed the plant’s control system to adjust fuel injection rates dynamically, improving energy efficiency by 5% and preventing speed-related tripping events. Additionally, the keyphasor signal enabled accurate phase analysis, helping maintenance teams detect a developing gear tooth defect before it caused catastrophic failure.
In comparison to similar speed monitoring solutions, the BENTLY 3500/92 offers superior multi-probe compatibility and diagnostic depth, ensuring seamless integration with the 3500 system’s comprehensive monitoring architecture. Its dual-channel redundancy and advanced signal conditioning reduce reliance on external components, simplifying system design while enhancing reliability. Unlike many alternatives, it provides both analog and digital outputs, catering to a wide range of control and data acquisition needs.

BENTLY 3500/92
When selecting the BENTLY 3500/92, consider the following:
- System Integration: Ensure compatibility with your existing 3500 chassis and software to leverage full diagnostic and communication capabilities.
- Signal Requirements: Determine if your machinery requires single or dual-channel monitoring, and verify probe type compatibility (proximity vs. tachometer).
- Environmental Demands: Confirm the module’s temperature and vibration resistance meet your site’s conditions, especially for high-speed or high-vibration applications.
- Data Output Needs: Assess whether analog, digital, or both output types are necessary for your control system or data analytics platform.
- Installation: Follow BENTLY’s guidelines for proper rack mounting and wiring to ensure signal integrity and prevent electromagnetic interference (EMI).
- Calibration: Use certified calibration tools to verify frequency response and signal accuracy during commissioning and periodic maintenance.
- Probe Alignment: Ensure proximity probes are correctly positioned and calibrated to avoid measurement errors caused by incorrect air gap or misalignment.
- Redundancy Testing: Regularly test dual-channel functionality to ensure failover mechanisms operate correctly in the event of a probe or cable failure.
Shanxi Xinyeda International Trading Co., Ltd. is your trusted partner, we provide and other automation spare parts sales and technical support. Please visit our website www.xydcontrol.com or contact us and we will be happy to serve you.
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